Let us call a conjoined NP properly containing a plural "multiply plural". 'The boys and the girls' is a multiply plural NP while 'John and Mary' or 'the boys' are "simply plural". The question addressed here is whether multiply plural NPs differ semantically from simple plural NPs. I contrast two theories which differ in their answer to this question as a result of a difference in the meaning they assign to 'and'. According to one theory, the "union theory", every felicitous plural NP denotes a set-like entity all of whose members are individuals (individuals do not themselves have members). On the "sets theory", felicitous multiply plural NPs denote entities that have two or more members some or all of which are not individuals. For example, 'the boys and the girls', if felicitous, denotes an entity having two members, one being the entity denoted by 'the boys', the other the entity denoted by 'the girls'. Each of these latter two entities have individuals as members. It follows on the sets theory that 'the boys and the girls' refers to a different entity than does the NP 'the children'. According to the union theory, the entity that 'the boys and the girls' refers to has only individuals as members. It is the same entity that 'the children' refers to. Syntactic complexity is mirrored in semantic complexity on the sets theory but not on the union theory. I will argue that English predicate extensions are not sensitive to the semantic distinctions present exclusively in sets. The distinctions of the sets theory cannot therefore affect truth conditions and hence it should yield to the union theory. In the course of this argument, I introduce a new context dependent analysis of distributivity. The apparent coreference, in some contexts, of singular collective and plural terms, for example 'the Senate' and 'the Senators', has been used to argue for the sets theory. In response, I argue that the referent of a singular collective NP is different in kind from the referent of a non-collective plural.